Conventionally, as a method of jointing metal plates together is known the one that the metal plates are swaged and crimped. The joint by using the above method, however, depends on residual stress or contact by the crimp, and thus has insufficient electric characteristics. Furthermore there have been posed drawbacks that the above contact of the metal plates has many spaces, making it difficult to secure longitudinal electric characteristics in view of corrosion. Furthermore, in order to secure electric characteristics to melt metal plates, for example, with gas or plasma so as to weld the metal plates to each other, it is perceived there also has been posed drawback that its difficulty to automate the method ill-adapts to mass product, and this makes it expensive to make.
Thereby, in order to resolve the aforementioned drawbacks, in the PTL 1, as a method of jointing metal plates together is suggested a method of jointing the metal plates together 110, 111 as shown in FIGS. 7 and 8, by cutting the two metal plates 110, 111, with their stacked, along a cut line L12 extending from one end of a bend line L11 passing the side away from the bend line L11 to the other end of the bend line L11, and by pressing, like bending, a part surrounded by the cut line L12 and the bend line L11 of the two metal plates 110, 111 along the bend line L11, jointing the metal plates 110, 111 together.
This method allows the part surrounded by the cut line L12 and the bend line L11 of the two metal plates 110, 111 to depress while a cut surface inside the cut line L12 rubs on a cut surface outside the cut line L12. This friction makes oxidation layer of the cut surface removed, its new surface exposed, an outside and an inside of the cut line L12 adhered, and metal plates jointed together. The metal plate joint body 101 with the metal joint is provided with a pair of projections 113 projecting in a press direction (namely, the arrow Z) by pressing the part surrounded by the cut line L12 and the bend line L11. The projection 113 is formed so as its top view is trapezoidal-shaped, and short width sides of the pair of trapezoidal-shaped projections (namely, the bend line L11) are each arranged opposed to each other in an interval.
Furthermore, a die using for pressing the two metal plates 110, 111 has a pair of press jigs tapered gradually toward tip thereof. This pair of press jigs is arranged in an interval where the pair of trapezoidal-shaped projections 113 are each formed.
The metal joint described in the PTL 1 was capable of good electrical characteristics by providing metal joint. Disadvantageously, when the metal joint set forth in the PTL 1 experiences drop and impact test, joint thereof disengaged, or some good electric characteristics may worsen. Namely, there has been posed drawback that mechanical strength is insufficient while the metal joint set forth in the PTL 1 may have good electric characteristics.
The PTL 2 discloses that as a method of jointing metal plates together as shown in FIG. 9 is advocated metal joint of forming swaged joint 114 by like plastically deforming such as, with two metal plates 110, 111 stacked together, a local thereof is circularly depressed. The swaged joint 114 has a part of the metal plate 110 engaged in the side of the metal plate 111. The metal joint described in the PTL 2, however, has posed drawbacks that rotation force exerting thereon made it easy to disengage.